First detection of tick-borne pathogens of dogs from Malta

Canine Babesiosis Caused by Large Babesia Species: Global Prevalence and Risk Factors-A Review

Canine babesiosis is a disease caused by protozoan pathogens belonging to the genus Babesia. Four species of large Babesia cause canine babesiosis (B. canis, B. rossi, B. vogeli, and the informally named B. coco). Although canine babesiosis has a worldwide distribution, different species occur in specific regions: B. rossi in sub-Saharan Africa, B. canis in Europe and Asia, and B. coco in the Eastern Atlantic United States, while B. vogeli occurs in Africa, southern parts of Europe and Asia, northern Australia, southern regions of North America, and in South America. B. vogeli is the most prevalent large Babesia species globally. This results from its wide range of monotropic vector species, the mild or subclinical nature of infections, and likely the longest evolutionary association with dogs. The most important risk factors for infection by large Babesia spp. include living in rural areas, kennels or animal shelters, or regions endemic for the infection, the season of the year (which is associated with increased tick activity), infestation with ticks, and lack of treatment with acaricides.

Clinical, diagnostic and epidemiological implications of Hepatozoon spp., Babesia spp. and Leishmania infantum infection in cats and dogs in a Mediterranean periurban setting

Hepatozoon spp., Babesia spp. and Leishmania infantum are common parasites of dogs in Mediterranean countries and are less frequent in cats, particularly Babesia spp. and L. infantum. Moreover, there is limited information on coinfections between these parasites and on L. infantum's distribution in blood, skin and lymphoid tissue in cats. We used PCR and DNA sequencing to investigate the prevalence of these parasites and the aetiology of Hepatozoon spp. and Babesia spp., in blood, skin, spleen and lymph node samples from up to 212 stray cats and 82 abandoned dogs in southeast Spain. All except 2 dogs were healthy; instead, 112 cats had clinical signs. The estimated PCR prevalences (95% confidence interval) were 25% (19-31%) Hepatozoon felis in cats, 13% (6-21%) Hepatozoon canis in dogs, 1% (0-4%) Babesia vogeli in dogs, 0% Babesia spp. in cats and 21% (15-26%) and 44% (33-55%) L. infantum in cats and dogs, respectively, and infections were not associated with each other. Leishmania infantum prevalence in lymphoid tissue was significantly higher in dogs than in cats (p < 0.001), and dogs had higher parasite loads than cats (p = 0.012). Moreover, L. infantum prevalence was significantly higher in the skin and lymphoid tissue compared to blood in infected, asymptomatic animals but it was similar in cats with clinical signs, which also had higher parasite loads compared to infected, asymptomatic cats (p < 0.05). The study highlights significant differences between sympatric dogs and cats with respect to the parasite infections investigated, as well as the need to examine both lymphoid tissue and skin samples to maximise the sensitivity of L. infantum infection diagnosis.

Detection of Ticks and Tick-Borne Pathogens of Urban Stray Dogs in South Africa

This study aimed to identify ticks infesting dogs admitted to the Potchefstroom Animal Welfare Society (PAWS) and to detect tick-borne pathogens they are harbouring. A total of 592 ticks were collected from 61 stray dogs admitted to PAWS originating from several suburbs in and near Potchefstroom, South Africa. The dog ticks were identified as Haemaphysalis elliptica (39%) and Rhipicephalus sanguineus (61%) by both morphological and DNA analyses. Of these ticks, H. elliptica consisted of 67.5% (156/231) and 32.5% (75/231) female and male ticks, respectively, whilst R. sanguineus consisted of 48.5% (175/361) and 51.5% (186/361) female and male ticks, respectively. Microscopic examination of blood smears from engorged female ticks indicated overall occurrences of 0.5% (1/204) for Babesia spp. from R. sanguineus, 1% (2/204) of Anaplasma spp. from H. elliptica, and 22% (45/204) of Rickettsia spp. from both H. elliptica and R. sanguineus. Using pooled samples molecular detection of tick-borne pathogens indicated overall occurrences of 1% (1/104) for A. phagocytophilum in H. elliptica, 9.6% (10/104) of Rickettsia spp. in H. elliptica and R. sanguineus, 5.8% (6/104) of Ehrlichia canis in H. elliptica and R. sanguineus, and 13.5% (14/104) of Coxiella spp. in both H. elliptica and R. sanguineus. Additionally, PCR detected 6.5% (2/31) of Coxiella spp. DNA from H. elliptica eggs. Our data indicate that urban stray dogs admitted at PAWS are infested by H. elliptica and R. sanguineus ticks which are harbouring several pathogenic organisms known to cause tick-borne diseases.

Prevalence of Ehrlichia-, Babesia-, and Hepatozoon-infected brown dog ticks in Khon Kaen Province, Northeast Thailand

Background and Aim:

The brown dog tick, Rhipicephalus sanguineus sensu lato, is the most common tick found on domestic dogs in Southeast Asia, including Thailand. Canine tick-borne pathogens are a public health concern worldwide. Tick-borne diseases are diagnosed by identifying pathogens based on the morphological or molecular analyses of dog blood samples. However, the collection of ticks, a non-invasive procedure, is easier than drawing blood. This study aimed to demonstrate the usefulness of collecting brown dog ticks for the diagnosis of tick-borne diseases and for estimating the prevalence of tick-borne pathogens among companion dogs in Khon Kaen, Northeast Thailand.

Materials and Methods:

Seventy brown dog ticks from 70 companion dogs in Khon Kaen Province, Thailand, were evaluated for molecular evidence of tick-borne pathogens, including Babesia spp., Ehrlichia canis, and Hepatozoon canis. Ticks were collected from dogs at a private animal hospital based on the presence of at least one of the three inclusion criteria: fever, anorexia, or lethargy. Molecular diagnosis was performed using conventional polymerase chain reaction for the detection of pathogens.

Results:

Of the 70 ticks collected from 70 sick dogs, 55 (78.57%) were positive for tick-borne pathogens. The most common infection was a single infection with H. canis (65.71%) followed by Babesia spp. (31.43%) and E. canis (30.00%). Coinfection was observed in 14 ticks (20.00%), and coinfection with Babesia spp. and E. canis was the most prevalent double infection (n = 6). The prevalence of coinfection was identical for H. canis mixed with Babesia spp. and H. canis mixed with E. canis (n = 4).

Conclusion:

The present study showed that tick-borne pathogens are highly prevalent among companion dogs in Khon Kaen Province. Therefore, we encourage an increase in tick control or the reduction and prevention of tick-borne diseases in this region. Furthermore, this study revealed that ticks are valuable samples for the molecular detection of tick-borne pathogens.

Epidemiology, Diagnosis, and Control of Canine Infectious Cyclic Thrombocytopenia and Granulocytic Anaplasmosis: Emerging Diseases of Veterinary and Public Health Significance

This review highlights the diagnostic methods used, the control strategies adopted, and the global epidemiological status of canine cyclic thrombocytopenia and granulocytic anaplasmosis at the animal–human interface. Canine anaplasmosis is an important worldwide disease, mainly caused by Anaplasma platys and A. phagocytophilum with zoonotic implications. A. platys chiefly infects platelets in canids, while A. phagocytophilum is the most common zoonotic pathogen infecting neutrophils of various vertebrate hosts. Diagnosis is based on the identification of clinical signs, the recognition of intracellular inclusions observed by microscopic observation of stained blood smear, and/or methods detecting antibodies or nucleic acids, although DNA sequencing is usually required to confirm the pathogenic strain. Serological cross-reactivity is the main problem in serodiagnosis. Prevalence varies from area to area depending on tick exposure. Tetracyclines are significant drugs for human and animal anaplasmosis. No universal vaccine is yet available that protects against diverse geographic strains. The control of canine anaplasmosis therefore relies on the detection of vectors/reservoirs, control of tick vectors, and prevention of iatrogenic/mechanical transmission. The control strategies for human anaplasmosis include reducing high-risk tick contact activities (such as gardening and hiking), careful blood transfusion, by passing immunosuppression, recognizing, and control of reservoirs/vectors.

Investigation on haplotypes of ixodid ticks and retrospective finding of Borrelia miyamotoi in bank vole (Myodes glareolus) in Switzerland

The current status of tick species, important tick-borne bacteria and protozoan parasites is well-documented in Switzerland. However, reports on the genetic diversity and geographical relationships of tick species in this country appear to be in part lacking or outdated. Thus, the aim of this study was to collect ticks from various host species in southern Switzerland, to compare them in a geographical context and to screen in these samples rare tick-borne pathogens hitherto not reported or having low prevalence in Switzerland. In 2019-2020 altogether 177 ixodid ticks were collected from the vegetation, as well as from humans (n = 17), dogs (n = 23), cats (n = 41), red deer (n = 8), a European rabbit and a European hedgehog at 25 locations in three cantons of south Switzerland. Tick species were identified morphologically, followed by DNA extraction and comparison of mitochondrial haplotypes with molecular-phylogenetic methods. Tick DNA extracts, as well as sixty-two rodent liver or spleen tissue DNA extracts (representing six species) available from 2005 to 2006 were screened for trypanosomes, Occidentia massiliensis and Borrelia miyamotoi. Morphologically, three tick species were identified: Ixodes ricinus (n = 170), Rhipicephalus sanguineus sensu lato (n = 6) and I. hexagonus (n = 1). In contrast to companion animals (dogs, cats) immature ticks (larvae and nymphs) predominated on humans, which was a highly significant association (P < 0.0001). Molecular comparison of the cytochrome c oxidase subunit I (cox1) gene with GenBank data established the species as R. sanguineus sensu stricto and confirmed I. hexagonus, both showing 99.8-100% sequence identity to conspecific ticks from northern Italy. Seventy-nine specimens morphologically identified as I. ricinus revealed high 16S rRNA gene haplotype diversity and represented two phylogenetic groups. Two I. ricinus haplotypes from Switzerland belonged to the same haplogroup with I. inopinatus from Spain, Germany and Austria as well as with I. ricinus reported from a broad geographical range of Europe (including Italy, the Netherlands, Poland, Latvia and Sweden). All 141 tick DNA extracts (from five R. sanguineus s.l., 135 I. ricinus and one I. hexagonus) and 62 rodent tissue DNA extracts were negative for trypanosomes and O. massiliensis. However, B. miyamotoi was identified in a bank vole (Myodes glareolus) and three ticks by sequencing. From Switzerland, this is the first report of tick haplotypes that are phylogenetically closely related to I. inopinatus. However, based on their morphology, both specimens are considered as I. ricinus. These results highlight the importance that the identification of I. inopinatus should be based on coherent morphologic and molecular properties. This is also the first report of rodent-borne B. miyamotoi in Switzerland. Taking into account the year of collection (2005), in a chronological order this might be the first indication of B. miyamotoi in any rodent species in Europe.

Molecular survey of vector-borne diseases in two groups of domestic dogs from Lisbon, Portugal

BACKGROUND

Canine vector-borne diseases (CVBDs) are caused by a wide range of pathogens transmitted by arthropods. They have been an issue of growing importance in recent years; however, there is limited information about the vector-borne pathogens circulating in Portugal. The aim of the present study was to detect canine vector-borne bacteria and protozoa of veterinary and zoonotic importance using molecular methods.

METHODS

One hundred and forty-two dogs from Lisbon, southern Portugal, were tested: 48 dogs from a veterinary hospital clinically suspected of vector-borne diseases and 94 apparently healthy dogs from shelters. Anaplasma spp./Ehrlichia spp., Babesia/Theileria spp., Hepatozoon spp., and Mycoplasma spp. infections were detected by PCR from blood samples and examined under light microscopy. Other information including clinical status and diagnostic test results were collected for each animal.

RESULTS

Infections were detected by PCR in 48 (33.80%) dogs. Single infections were found in 35 dogs (24.64%), and co-infections were found in 13 (9.15%) dogs. Twenty-nine (20.42%) dogs were positive for Hepatozoon spp., 15 (10.56%) for Mycoplasma spp., 11 (7.75%) for Anaplasma spp./Ehrlichia spp., and six (4.21%) for Babesia spp. DNA sequencing was used to identify Babesia vogeli (2.81%), Babesia canis (1.40%), Hepatozoon canis (20.42%), Mycoplasma haematoparvum (2.11%), Mycoplasma haemocanis (8.45%), Anaplasma platys (7.04%), and Ehrlichia canis (0.70%).

CONCLUSIONS

This is the first molecular identification of B. canis and M. haematoparvum in dogs from southern Portugal. This study highlights the importance of molecular methods to identify CVBD pathogens in endemic areas and helps to guide the clinical approach of veterinarians in practice.

Hepatozoon canis in hunting dogs from Southern Italy: distribution and risk factors

Hepatozoon canis is a hemoprotozoan organism that infects domestic and wild carnivores throughout much of Europe. The parasite is mainly transmitted through the ingestion of infected ticks containing mature oocysts. The aims of the present survey were to determine the prevalence of H. canis in hunting dogs living in Southern Italy and to assess potential infection risk factors. DNA extracted from whole blood samples, collected from 1433 apparently healthy dogs living in the Napoli, Avellino, and Salerno provinces of Campania region (Southern Italy), was tested by a quantitative real-time polymerase chain reaction (qPCR) assay to amplify H. canis. Furthermore, the investigated dog population was also screened by qPCR for the presence of Ehrlichia canis, a major tick-borne pathogen in Southern Italy, in order to assess possible co-infections. Two hundred dogs were H. canis PCR-positive, resulting in an overall prevalence of 14.0% (CI 12.2–15.9). Breed category (P < 0.0001), hair coat length (P = 0.015), and province of residence (P < 0.0001) represented significant risk factors for H. canis infection. The presence of H. canis DNA was also significantly associated with E. canis PCR positivity (P < 0.0001). Hunting dogs in Campania region (Southern Italy) are frequently exposed to H. canis, and the infection is potentially associated with close contact with wildlife. Further studies are needed to assess the pathogenic potential of H. canis, as well as the epidemiological relationships between hunting dogs and wild animal populations sharing the same habitats in Southern Italy.

Detection of Flea-Borne Pathogens from Cats and Fleas in a Maltese Shelter

In a sanctuary located on the island of Malta, 23 clinically healthy cats randomly selected were sampled for blood and fleas. Only fleas were collected from 35 cats. All fleas were identified as Ctenocephalides felis, except for one specimen of Ctenocephalides canis. To the best of the authors' knowledge, this may be the first time to establish the occurrence of Bartonella koehlerae and B. clarridgeiae, as well as of Candidatus Mycoplasma haemominutum in the blood samples of 11 cats (47.82% [95% CI: 29.33-67.04]) with conventional PCR assays. One or more pathogens were found in 54 (96.42% [95% CI: 86.74-99.70]) out of 56 pooled flea samples, the most prevalent was Rickettsia felis. The DNA of Bartonella henselae, the commonest etiological agent of cat scratch disease, was detected first time in a pooled flea sample of a cat.

First records and molecular-phylogenetic analyses of three tick species (Ixodes kaiseri, Hyalomma lusitanicum and Ornithodoros coniceps) from Malta

The Maltese islands are situated south of mainland Europe and north of Africa, therefore are expected to share tick species and tick-borne pathogens with both continents. This situation highlights the importance of studying ticks in this country. Nevertheless, the tick fauna of Malta appears to be a seldom investigated issue, with hitherto only five tick species reported in the country. Here, as part of a tick collection campaign continuing since 2016 in Malta, three tick species new to the country are reported and analyzed in comparison with GenBank data. Ixodes kaiseri (collected from North African hedgehog in Malta) had unique cytochrome c oxidase subunit I (cox1) and 16S rRNA gene haplotypes (with 98.1-99.3 % sequence identity to I. kaiseri from Europe and China). Phylogenetically, these haplotypes from Malta clustered separately from other, mainland-associated haplotypes, with high support. On the other hand, Ornithodoros coniceps (collected from domestic chicken in Malta) had identical or nearly identical cox1 and 16S rRNA gene haplotypes with soft ticks reported from France, northern Africa and western African islands, similarly to Hyalomma lusitanicum (collected from rabbit and cat in Malta) in comparison with conspecific ticks in Spain and Portugal. These results are most likely related to differences in host associations and corresponding translocality of these three tick species. Taken together, results of the present study add three new tick species to those five already known to be present in Malta.

Hepatozoon canis in three imported dogs: a new tickborne disease reaching the United Kingdom

An increasing number of non-endemic vectorborne pathogens have been described in dogs imported to the UK in the past two decades. Recently, an outbreak of canine babesiosis in south-east England has raised veterinary awareness with regard to the impact of such diseases on the UK canine population. Canine hepatozoonosis, caused by Hepatozoon canis and transmitted by the ingestion of Rhipicephalus sanguineus ticks, is widespread in the Mediterranean basin. Herein we describe the first three molecularly confirmed clinical cases of canine hepatozoonosis in dogs imported into the UK. Veterinarians in the UK should be aware of H canis as a potential infection in imported dogs, especially in the face of the expanding distribution of R sanguineus ticks in Europe.

Detection of Anaplasmataceae agents and co-infection with other tick-borne protozoa in dogs and Rhipicephalus sanguineus sensu lato ticks

Anaplasmosis and ehrlichiosis are of serious health concern worldwide for animals and humans. In the present study, we report the occurrence of Anaplasma platys and Ehrlichia canis in dogs and Rhipicephalus sanguineus sensu lato (s.l.) ticks from Peninsular Malaysia using a nested polymerase chain reaction assay based on amplification of the 16S rRNA gene. Anaplasma platys was detected from dogs and ticks with prevalence rates of 3.3% (8/240) and 2.9% (4/140), respectively. On the other hand, 12.9% (31/240) of the dogs and 0.7% (1/140) of the ticks were tested positive for E. canis. Additionally, co-infections of A. platys and E. canis with Babesia or Hepatozoon protozoa were also noted in this study. Double infection (E. canis + B. gibsoni) was observed in tick, whereas triple infections (E. canis + A. platys + B. vogeli and E. canis + A. platys + H. canis) were found in dogs. This study represents the first evidence of A. platys DNA in R. sanguineus s.l. in Malaysia.

Molecular detection of Hepatozoon canis in dogs from Kerala

India has a wide range of agro-climatic zones which is highly conducive for a diverse range of vectors and canines are continuously exposed to the risk of spectrum of tick borne protozoan diseases. The brown dog tick, Rhipicephalus sanguineus is widely prevalent among dogs in Kerala and there is a high prevalence of this tick transmitted Babesia and Ehrlichia spp. infection. However, the incidence of Hepatozoon canis transmitted by the same tick species had not been reported in the state since 2004. Preliminary screening of client owned dogs revealed six dogs to be positive for typical gelatin capsule shaped gamonts of H. canis within neutrophils in blood smear by microscopic examination. A PCR assay was standardized to amplify a specific 737 bp fragment of 18S rRNA gene of H. canis. Phylogenetic analysis revealed closest relationship with West Indies isolate deposited at GenBank database. The present study records the molecular detection of this haemoparasite in the state, for the first time.

Clinically-diagnosed Mediterranean Spotted Fever in Malta

BACKGROUND

Mediterranean Spotted Fever (MSF) is a tick-borne zoonosis caused by Rickettsia conorii which is endemic in Malta, an island in the South Mediterranean that is a popular tourist destination. Diagnosis is frequently based on clinical manifestations as laboratory results are often limited to a retrospective diagnosis. We describe the clinical presentation, diagnosis and treatment of children <16 years who presented with MSF from 2011 to 2016.

METHOD

The demographics, clinical findings, laboratory results, management and outcome of all children hospitalised with suspected MSF based on the presence of fever and an eschar, were retrieved from their case notes.

RESULTS

Over the five-year study period six children, aged between 17 months and 15 years, were diagnosed with MSF. All children had contact with ticks and the majority presented in summer. Laboratory results were non-specific and included elevated inflammatory markers, lymphocytosis/lymphopenia and hyponatraemia. Serological and molecular techniques were used for diagnosis. Response to clarithromycin or doxycycline was immediate.

CONCLUSION

MSF should be included in the differential diagnosis of fever, rash and an eschar in children who travel to Malta. Despite advances in molecular diagnostics, clinical diagnosis remains important in the management of children with suspected MSF.

First description of the pathogenicity of Babesia vogeli in experimentally infected dogs

Babesiosis is a tick-borne disease that occurs worldwide with the most recognized Babesia species that infect dogs being Babesia canis, B. vogeli, B. rossi and B. gibsoni. While B. vogeli is reported in dogs worldwide, clinical and laboratory data on infections is based on reports of naturally infected dogs. To provide reliable data on the clinical and laboratory abnormalities associated with acute and more chronic infections in healthy dogs free of other tick-borne diseases, we experimentally infected dogs with a Chinese strain of B. vogeli. All of the six infected Beagles, three of which were splenectomized, became infected with B. vogeli detected in blood smears taken the day following infection and the organism detected by FRET-qPCRs in most blood samples (77/86; 90%) collected about every 4 days until the end of the experiment on day 95. All the infected dogs showed fever, partial anorexia and malaise that was more severe in the splenectomized dogs that did not gain weight for three weeks in the period after initial infection. Regenerative anemia, thrombocytopenia and decreased white blood cell counts were seen in all dogs but were more severe in the splenectomized dogs, of which two had life threatening infections and had to be removed from the study for treatment. Following re-infection on day 66, none of the dogs showed clinical signs and copy numbers did not change significantly although all the dogs were negative by FRET-qPCR on at least some of the subsequent sampling days. Laboratory values in the non-splenectomized dogs were relatively unchanged while in the splenectomized dog there was a temporary small increase in the platelet and white blood cell counts and a temporary slight worsening of the anemia. In summary, our study shows dogs experimentally infected with a B. vogeli strain from China develop only mild clinical signs that are followed by asymptomatic infections that can last for least 95 days. In splenectomized dogs, however, severe life threatening signs may develop.